Tired of evenings out that always seem to feature those Valley standbys: flip-flops and cheap margaritas? There's no better cure than a trip to an Arizona Opera performance. It's the one of few things in town that people really do get dressed up for. And while the good seats aren't cheap  the opera wants a $2,500 donation plus $121 a show just to sit in certain areas  you can be frugal, with back-row tickets starting at $34 on weekdays. Even there, though, you're going to feel like a million dollars. Just leave the plastic sandals at home.